Hammer driven wrench



p 13, 1966 G. I. EKSTROM ETAL 3,272,035

HAMMER DRIVEN WRENCH Filed April 20, 1964 INVENTQRS.

GOSTA IVAR EKSTROM a 2 BY sne HUGO NORDAHL WML ATTORNEY United States Patent 3,272,035 HAMMER DRIVEN WRENCH Giista Ivar Ekstriim and Stig Hugo Nordahl, Nacka, Sweden, assignors to Atlas Copco Aktiebolag, Nacka, Sweden, a corporation of Sweden Filed Apr. 20, 1964, Ser. No. 361,106 Claims priority, application Sweden, Apr. 24, 1963, 4,467/ 63 9 Claims. (Cl. 8152.3)

The invention relates to hammer driven wrenches of the type operated by impacts and including power operated reciprocating hammer means for delivering a series of rotational blows to a wrench body. Wrenches of this kind are used for tightening and loosening of very large nuts, for example in connection with repairs of ship engines. In such applications the space around the nuts usually is very restricted and a drawback of the wrenches used heretofore has been their inapplicability or poor and uneconomic performance in such spaces.

It is a primary object of the invention to provide an improved wrench of the above character having a simplified design, including a minimum of details, and being effectively applicable on nuts disposed in a restricted space. For these and other purposes there is according to the invention provided a hammer driven wrench operated by impacts and including power operated reciprocating hammer means for delivering a series of rotational blows to a wrench body.

The invention will be described more in detail by the aid of the accompanying drawing in which FIG. 1 shows a top plan view of a hammer driven wrench according to the invention with the front portion of the hammer means depicted in section. FIG. 2 is a section on the line 22 in FIG. 1 and FIG. 3 is a section on the line 33 in FIG. 1.

The illustrative hammer driven wrench consists of a wrench body or socket which preferably is annular in shape and has an inner nut receiving aperture 11. As an alternative a wrench body may be contemplated having a laterally open jaw. The wrench body 10 is provided with an outer lug 12 having an impact receiving shoulder 13 formed thereon for taking up tangential or rotational blows from a hammer motor 14. The lug 12 is disposed in the central transverse plane of the wrench aperture 11 and socket 10 and coplanar with the longitudinal axis of the hammer motor 14.

The hammer motor 14 preferably consists of a pneumatic hammer 15 with a hammer piston 16 reciprocable therein under the action of pressure fluid in a manner well known in the art and therefore not illustrated in detail. The piston 16 delivers its blows to an anvil 17 which is kept in contact with the shoulder 13 on the lug 12. The front end of the hammer 15 is fixed in a head portion or clamping socket 18 provided with a slot 19 and a transverse clamping bolt 20. By tensioning of the bolt 20 the socket 18 can be compressed thanks to the slot 19 so that the hammer 15 is clamped fast. A transverse groove 21 in the hammer 15 coacts with the clamping bolt 20 and prevents axial movement of the hammer 15 as long as the bolt 20 is in place.

From the clamping socket 18 there project a pair of spaced ears 22 laterally. Between the cars 22 is inserted a pivot 23 which has a reduced central portion 24 and widened end portions carried by .the ears 22. Around the central portion 24 there is mounted a highly elastic sleeve 25 preferably of rubber, which is interposed between the ears 22 and keeps the pivot 23 in place, the widened end portions of the pivot 23 being unable to pass the sleeve 25 in axial direction. A number of peripheral annular grooves 26 on the sleeve 25 are intended for 3,272,635 Patented Sept. 33, 1966 ice purposes of making possible considerable radial elastic compression of the sleeve.

Within an acute angle from the lug 12 there projects a second lug 27 substantially radially from the wrench body 10, said second lug 27 being coplanar with the lug 12. The second lug 27 is provided with a hole 28 re ceiving the rubber sleeve 25 together with the pivot 23. The lug 27 projects in between the ears 22 of the clamping socket 18. The pivot 23 and the rubber sleeve 25 provide a resilient joint directly connecting the hammer motor 14 with the wrench body 10. By means of an abutment 29 on the lug 27 and a cooperating abutment 30 between the ears 22 of the clamping socket 18 the angular movability of the wrench body 10 around the joint 23, 25 is restricted to a suitable value preferably somewhat larger than the amplitude of the impact delivering end on the anvil 17 of the hammer motor 14. The joint 23, 25 is furthermore preferably so disposed that the longitudinal central axis of the hammer motor 14 always forms an obtuse angle with a straight line drawn from the middle of the wrench body 10 to the point of contact between the anvil 17 and the shoulder 13 on the lug 12, by which design the width of the wrench may be kept to a minimum.

During use the jaw 11 is placed over the nut to be tightened or loosened, whereupon the hammer motor 14 together with the socket 18 in handle-like manner are turned about the joint 23, 25 and pushed by the operator to maintain contact between the anvil 17 and the impact receiving shoulder 13. With the hammer motor 14 in operation the hammer piston 16 will transmit via the anvil 17 rotational blows to the lug 12. Thanks to the radially compressible elastic sleeve 25 of the joint 23, 25 the wrench body 10 will be free to move angularly around its axis upon each rotational blow away from the socket 18, whereby the nut is loosened or tightened. The abutments 29, 30 between the lug 27 and the clamping socket 18 are provided for limiting such angular movement of the wrench body 10 and for safeguarding that the anvil 17 always will be in immediate adjacency to the shoulder 13. Upon each blow the abutting relationship between the anvil 17 and the shoulder 13 is immediately re-established by the torque exerted by the operator on the hammer motor 14.

Subsequent to each rotational blow there is evidently produced a momentary radial compression of and storing of energy in the rubber sleeve 25. Under its subsequent elastic expansion the sleeve 25 due to the chosen disposition of the pivot 23 tends to move the pivot 23 in the general direction of the shoulder 13. The head portion 18 and the hammer motor 14 are thus urged elastically towards the shoulder 13 so that the operator is assisted in applying torque to the hammer motor 14.

With the piston '16 inoperative the hammer motor 14 obviously may be used as a wrench handle for manual turning of the socket or wrench body 10 without impacts and under transmission of a considerable substantially constant torque.

As an alternative embodiment identical in operation there may be provided elastic sleeves between the ends of the pivot 23 and their cooperating bores in the cars 22 in which case the lug 27 will be journalled directly on the central portion of the pivot 24.

What we claim is:

1. A hammer driven wrench operated by impacts and including power operated reciprocating hammer means for delivering a series of rotational blows to a wrench body, said hammer driven wrench comprising a wrench body, a radially directed outer lug centrally on and integral with said wrench body, said lug having a radial shoulder thereon, a pivot on said wrench body spaced from but parallel with the axis of rotation of said wrench body and angularly spaced from said lug, handle means mounted on said wrench body for limited bidirectional rotation thereon on said pivot, said handle means including a head portion carrying said pivot and a shaft portion disposed substantially tangentially to said wrench body and with the longitudinal axis on said shaft portion intersecting said shoulder, said shaft portion consisting of a pressure fluid operated hammer having an impact delivering surface disposed concentrically with respect to the axis of said shaft portion and adjacent said shoulder, and said hammer being operable for imparting rotational blows by said impact delivering surface to said shoulder.

2. A hammer driven wrench as set forth in claim 1 in which elastic means are associated with said pivot for providing a certain elastic movability perpendicularly to said pivot between said wrench body and said handle means.

3. A hammer driven wrench as set forth in claim 1 in which said pivot is offset laterally with respect to the axis of said shaft portion.

4. A hammer driven wrench as set forth in claim 2 in which said elastic means is a radially compressible elastic sleeve mounted on said pivot and forming part of the pivotal connection between said head portion and said wrench body.

5. A hammer driven wrench as set forth in claim 1 in which there are provided cooperating abutments on said head portion and on said Wrench body for restricting the angular movability about said pivot therebetween.

6. A hammer driven wrench as set forth in claim 1 in which said shoulder is formed on a first radial lug on said wrench body while said pivot is carried by a second lug on said wrench body angularly spaced from said first lug.

7. A hammer driven wrench operated by impacts and including power operated reciprocated hammer means for delivering a series of rotational blows to a wrench body, said wrench comprising a wrench body, a first radial outer lug centrally on and integral with said wrench body, said first lug having a radial shoulder thereon, a second outer lug on said wrench body angularly spaced from said first lug, a pivot carried by said second lug in substantially parallel relation to the axis of rotation of said wrench body, a pneumatic hammer mounted at the impact delivering end thereof on said pivot of said second lug for limited bidirectional rotation relative to said wrench body and with said impact delivering end disposed adjacent said shoulder, and said hammer having means thereon operable for imparting rotational blows to said shoulder.

8. A hammer driven wrench as set forth in claim 7 in which elastic means are associated with said pivot for momentarily storing a portion of the energy of each bl-ow delivered to said wrench body and for releasing said stored energy by biasing said impact delivering end towards said shoulder subsequent to each blow.

9. A hammer driven wrench operated by impacts and including power operated reciprocating hammer means for delivering a series of rotational blows to a wrench body, said wrench comprising a wrench body, a radially directed outer shoulder centrally on and integral with said wrench body, pivot means on and connected to the outside of said wrench body and extending in parallel relation to the axis of rotation thereof, a pneumatic hammer mounted at the impact delivering end thereof on said wrench body for limited bidirectional rotation thereon on said pivot means, said impact delivering end being disposed adjacent said shoulder, said hammer having means thereon operable for imparting rotational blows to said shoulder, and a radially compressible elastic sleeve mounted on said pivot means and forming part of the pivotal connection between said head portion and said wrench body for resiliently receiving a portion of the energy of each blow delivered to said wrench body and for releasing said received energy by biasing said impact delivering end towards said shoulder subsequent to each blow.

References Cited by the Examiner UNITED STATES PATENTS 2,086,261 7/1937 Douglas 81-52.3 2,112,693 3/1938 Douglas 81-S2.3 2,119,968 6/1938 Shafi 8l52.3 2,362,499 11/ 1944 Porter 81-523 WILLIAM FELDMAN, Primary Examiner. J. L. JONES, 1a., Assistant Examiner. 

1. A HAMMER DRIVEN WRENCH OPERATED BY IMPACTS AND INCLUDING POWER OPERATED RECIPROCATING HAMMER MEANS FOR DELIVERING A SERIES OF ROTATIONAL BLOWS TO A WRENCH BODY, SAID HAMMER DRIVEN WRENCH COMPRISING A WRENCH BODY, A RADIALLY DIRECTED OUTER LUG CENTRALLY ON AND INTEGRAL WITH SAID WRENCH BODY, SAID LUG HAVING A RADIAL SHOULDER THEREON, A PIVOT ON SAID WRENCH BODY SPACED FROM BUT PARALLEL WITH THE AXIS OF ROTATION OF SAID WRENCH BODY AND ANGULARLY SPACED FROM SAID LUG, HANDLE MEANS MOUNTED ON SAID WRENCH BODY FOR LIMITED BIDIRECTIONAL ROTATION THEREON SAID PIVOT, SAID HANDLE MEANS INCLUDING A HEAD PORTION CARRYING SAID PIVOT AND A SHAFT PORTION DISPOSED SUBSTANTIALLY TANGENTIALLY TO SAID WRENCH BODY AND WITH THE LONGITUDINAL AXIS ON SAID SHAFT PORTION INTERSECTION AND SHOULDER, SAID SHAFT PORTION CONSISTING OF A PRESSURE FLUID OPERATED HAMMER HAVING AN IMPACT DELIVERING SURFACE DISPOSED CONCENTRICALLY WITH RESPECT TO THE AXIS OF SAID SHAFT PORTION AND ADJACENT SAID SHOULDER, AND SAID HAMMER BEING OPERABLE FOR IMPARTING ROTATIONAL BLOWS BY SAID IMPACT DELIVERING SURFACE TO SAID SHOULDER. 